According to a report on ESPN, Stephen Ross made a modification to Parcells' contract to allow him leave at any time if he so chooses, and he gets to take the money with him for the remainder of the contract.
How much of this is true is anyone's guess (other than these two and Parcells' agent). But if it is true, it might be a nice compromise. Parcells wanted to work for Wayne and had an out in his contract if he sold the team. So far things look good between the new owner and him. By changing the contract, Ross made an argument for Parcells to stay - "You're running a good football operation, and I don't want you to think that I'm going to force you to stay under contract. Now lets get to business."
And Parcells gets his ego stroked. If things continue to go well, he stays. If he feels Ross isn't playing fair, or is meddling, he leaves.